Electrochemical and microstructural performance of steel reinforced carbonated and non-carbonated mortars in a saline environment
- Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials
This paper describes work in progress to investigate the combined effect of chloride ions and carbonation in the corrosion of steel in mortar specimens. The corrosion behavior was investigated by electrochemical techniques, namely linear polarization resistance. Scanning electron microscopy (SEM) and energy dispersive x-ray microanalysis were used to study the microstructure of the steel/paste interface and the chemistry and distribution of the corrosion products. Eight mortar specimens were cast with water/cement and cement/sand ratios of 0.5 and 1/3, respectively. After 7 days of curing in plastic bags two samples were exposed to a saline environment (inversion in a 0.5M NaCl solution), another five were carbonated (in 100% C0{sub 2} and 65% RH), and the last one was kept immersed in water as reference. After 5 months, some of the specimens were switched round (i.e. the carbonated ones were immersed in 0.5M NACI), while one specimen from each environment remained in the initial environment. For the specimen which was placed in the C0{sub 2} environment after immersion in NaCl, the exposure time was not long enough to fully carbonate the mortar after the formation of observable amounts of corrosion products, although corrosion can be detected electrochemically. In the case of the specimens in a C0{sub 2} atmosphere, the corrosion rate was very low until full carbonation. When a specimen was then put in an NaCl solution, the corrosion rate increased almost immediately. The exposure time of the specimens was not long enough to produce any conclusive results, but the samples in a NaCl solution began to corrode soon after exposure.
- OSTI ID:
- 109949
- Report Number(s):
- CONF-950304-; TRN: IM9543%%250
- Resource Relation:
- Conference: Corrosion `95: National Association of Corrosion Engineers (NACE) international annual conference and corrosion show, Orlando, FL (United States), 26-31 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Corrosion/95 conference papers; PB: 5788 p.
- Country of Publication:
- United States
- Language:
- English
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